Display Device

Abstract

Provided is a display device. The display device includes a substrate comprising a plurality of subpixels; a thin-film transistor on the substrate; a bonding layer on the thin-film transistor; a first area and a second area having a higher tangent delta value than the first area; and a plurality of light-emitting elements disposed in the first area of the bonding layer corresponding to the plurality of subpixels. The invention allows suppressing a bonding defect of a light-emitting element.

What is claimed is: 
     
         1 . A display device comprising:
 a substrate comprising a plurality of subpixels;   a thin-film transistor disposed on the substrate;   a bonding layer disposed on the thin-film transistor and comprising a first area, and a second area having a higher tangent delta value than the first area; and   a plurality of light-emitting elements disposed in the first area of the bonding layer corresponding to the plurality of subpixels,   wherein the tangent delta value is a dimensionless value obtained by dividing an indentation hardness value when calculated in N/mm 2  by an indentation modulus value when calculated in MPa.   
     
     
         2 . The display device of  claim 1 , wherein the tangent delta value of the first area is 0.01 or less, and the tangent delta value of the second area is 0.08 to 0.2. 
     
     
         3 . The display device of  claim 1 , wherein the second area is higher in hardness than the first area. 
     
     
         4 . The display device of  claim 1 , wherein the bonding layer comprises a binder resin, a photosensitive agent, and a first and a second functional monomers, wherein the second functional monomer is capable of forming a surface having a higher tangent delta value than the first functional monomer. 
     
     
         5 . The display device of  claim 4 , wherein the first functional monomer includes one or more compounds selected from a group consisting of diurethane dimethacrylate, polyethylene glycol dimethacrylate, bisphenol A (EO) 10 diacrylate, bisphenol A (EO) 30 diacrylate, tricyclodecane dimethanol diacrylate, tetraethylene glycol diacrylate, polyethylene glycol 200 diacrylate, polyethylene glycol 300 diacrylate, polyethylene glycol 400 diacrylate, polyethylene glycol 600 diacrylate, polyethylene glycol 1000 diacrylate, tris (2-hydroxyethyl) isocyanurate diacrylate, butylated hydroxyanisole, 2,6-di-tert-butyl-4-hydroxymethylphenol, butylated hydroxytoluene, propyl gallate, lauryl gallate, octyl gallate, 2,4,5-trihydroxybutyrophenone, tert-butylhydroquinone 3-aminophenol, 4-aminophenol, 4-methoxyphenol, 2,3,5-trimethylphenol, 2,4-dimethylphenol, 2,6-dimethylphenol, poly (4-vinylphenol), and 4-bromophenol. 
     
     
         6 . The display device of  claim 4 , wherein the second functional monomer includes one or more compounds selected from a group consisting of 1,4-butanediol diacrylate, 1,6-hexanediol diacrylate, 1,3-butylene glycol diacrylate, neopentyl glycol diacrylate, ethylene glycol diacrylate, diethylene glycol diacrylate, propylene glycol dimethacrylate, pentaerythritol tetraacrylate, pentaerythritol diacrylate, pentaerythritol triacrylate, dipentaerythritol triacrylate, dipentaerythritol pentaacrylate, pentaerythritol hexaacrylate, triethylene glycol diacrylate, polyethylene glycol diacrylate, dipentaerythritol diacrylate, sorbitol triacrylate, bisphenol A diacrylate derivatives, and trimethylpropanetriacrylate. 
     
     
         7 . The display device of  claim 4 , wherein a total content of the functional monomer including the first functional monomer and the second functional monomer is 10 to 70 parts by weight based on 100 parts by weight of the binder resin. 
     
     
         8 . The display device of  claim 1 , wherein a top surface of the first area further protrudes toward the plurality of light-emitting elements than a top surface of the second area. 
     
     
         9 . The display device of  claim 8 , further comprising:
 a stepped structure disposed below the bonding layer and comprising a protruding portion protruding toward the plurality of light-emitting elements corresponding to the first area.   
     
     
         10 . The display device of  claim 9 , further comprising:
 a planarization layer disposed on the thin-film transistor;   a plurality of reflective plates disposed on the planarization layer and respectively connected to the plurality of light-emitting elements; and   a passivation layer between the plurality of reflective plates and the bonding layer,   wherein the stepped structure is disposed between the plurality of reflective plates and the passivation layer is disposed between the passivation layer and the bonding layer.   
     
     
         11 . The display device of  claim 9 , further comprising:
 a planarization layer on the thin-film transistor;   a plurality of reflective plates disposed on the planarization layer and respectively connected to the plurality of light-emitting elements; and   a passivation layer disposed between the plurality of reflective plates and the bonding layer,   wherein the stepped structure is formed as the passivation layer.   
     
     
         12 . The display device of  claim 1 , wherein a concave-convex pattern is formed on a bottom surface of each of the plurality of light-emitting elements. 
     
     
         13 . The display device of  claim 12 , wherein a void is formed between the bonding layer and the concave-convex pattern, and a ratio of a height of the void to a height of the concave-convex pattern is 5 or less. 
     
     
         14 . The display device of  claim 12 , wherein each one of the bottom surfaces of the plurality of light-emitting elements is in contact with the bonding layer in the first area so that no void is formed between the bonding layer and the concave-convex pattern. 
     
     
         15 . The display device of  claim 12 , wherein each of the plurality of light-emitting elements comprises:
 a first semiconductor layer on the bonding layer;   a second semiconductor layer on the first semiconductor layer;   a light-emitting layer between the first semiconductor layer and the second semiconductor layer;   a first electrode disposed on the first semiconductor layer and disposed to be spaced apart from the light-emitting layer; and   a second electrode on the second semiconductor layer,   wherein a bottom surface of the first semiconductor layer is in direct contact with the first area of the bonding layer.   
     
     
         16 . The display device of  claim 1 , wherein a difference between the tangent delta value of the second area and the tangent delta value of the first area is 0.05 to 0.2. 
     
     
         17 . A display device comprising:
 a substrate comprising a plurality of subpixels;   a thin-film transistor disposed on the substrate;   a bonding layer comprising one or more sub-patterns and disposed on the thin-film transistor; and   a plurality of light-emitting elements disposed on the bonding layer corresponding to the plurality of subpixels,   wherein the sub-patterns of the bonding layer have a lower tangent delta value than an average tangent delta value of the whole bonding layer, and the plurality of light-emitting elements are aligned with the sub-patterns of the bonding layer, and   wherein the tangent delta value is a dimensionless value obtained by dividing the indentation hardness value when calculated in N/mm 2  by the indentation modulus value when calculated in MPa.   
     
     
         18 . The display device of  claim 17 , wherein the sub-patterns of the bonding layer have a tangent delta value that is lower than the tangent delta value of another area in the bonding layer by at least 0.05. 
     
     
         19 . The display device of  claim 17 , wherein the bonding layer comprises a binder resin, a photosensitive agent, and a first and a second functional monomers, wherein the second functional monomer is capable of forming a surface having a higher tangent delta value than the first functional monomer, and a total content of the functional monomer including the first functional monomer and the second functional monomer is 10 to 70 parts by weight based on 100 parts by weight of the binder resin. 
     
     
         20 . The display device of  claim 19 , wherein a content ratio between the first functional monomer and the second functional monomer is 3:1 to 1:1.